This is what I have done so far:
The notebook (Compaq 421) started crashing from the date of purchase. At my persistent claims, HP replaced ALL HARDWARES and reinstalled Windows7 and all drivers. It improved a little bit but still kept crashing.
Measures taken based on your recommendations
1. Hardware check
Overheating was not a problem—freeware check indicated CPU and GPU temperature is in normal range.
Power supply check—I have run the notebook only on battery for 24 hours. It crashed even on battery only mode. I had to conclude PSU is OK.
2. Stress test—I have run Prim95 for 24 hours. It did not lockup nor show any error message.
3. TDR Error Hotfix
I have download Microsoft Fix 50848 and run it—several times. Still crashes.
4. Window Parameter Reset
I have readjusted Visual Effect from “automatic setting (L)” to “adjust to most appropriate visual effect (P)”
I have “reset” the pagefile and adjusted the Virtual Memory to manual adjusting mode (initial 3,000 MB, Maximum 3 GB)
I have done system check by typing “SFC.EXE /SCANNOW” at 층 in administrator mode. The test results states that the system is free from error.
I also tried to do synchronizing adjustment—which procedure I cannot recall at the moment— but when I typed in “the recommended command” at command prompt, it did not responded as it is stated in the MS document. Some message indicating mismatch …
Thanks for reading